A Nazi Shipwreck Is Leaking Toxic Chemicals Into the North Sea

The remains of a Nazi patrol boat that was sunk by British bombs and gunfire during World War II is leaking toxic waste, including explosives and heavy metals, into its final resting place on the floor of the North Sea, reports a new study. The hazardous materials from the shipwreck have influenced the surrounding ecosystem, shedding light on the pollution that sunken vessels can introduce to undersea environments.

Eighty years ago, a Nazi convoy of battleships and support vessels attempted to race up the English Channel as part of a naval operation called Operation Cerberus, also known as the Channel Dash. On February 12, 1942, the Royal Air Force attacked the fleet off the coast of Belgium, sinking the Nazi patrol boat V-1302 John Mahn, a converted trawler that was part of the operation’s escort, and killing a dozen crew members. 

John Mahn now lies mostly intact under about 115 feet under the ocean surface, and it still contains unexploded depth charges and many hazardous contaminants. To better understand its impact on the seafloor, scientists led by Josefien Van Landuyt, a PhD student studying marine ecology at Ghent University, sampled sediments around the shipwreck, along with parts of its steel hull. 

The team discovered that the toxic pollutants such as nickel, copper, arsenic, and petrochemicals have seeped from the wreck into the adjacent habitats, which has affected the microbiology on the seafloor, according to a study published on Tuesday in Frontiers of Marine Science. The study is part of the North Sea Wrecks project, a research effort focused on the thousands of ship and aircraft wrecks that litter the floor of this sea.

“The wreck we studied was selected as a representative case study for the Belgian North Sea because of the type of ship, the suspected load in terms of fuel and munition, the time since it was sunk, local hydrology and how accessible it was to divers,” Van Landuyt said in an email to Motherboard. “It is one of twenty wrecks which were sampled for a larger international project called ‘North Sea Wrecks’ that are found all over different parts of the North Sea (Belgium, Norway, Germany, Denmark, The Netherlands).”

The team’s analysis revealed that the area around the ship’s coal bunker was particularly contaminated by toxic metals, and that harmful chemicals called polycyclic aromatic hydrocarbons (PAHs) were strewn near the wreck. These deposits actually changed the ecology of the region by supporting microbes, such as Rhodobacteraceae and Chromatiaceae, that degrade PAHs. Microbes from the Desulfobulbia family, which is fueled by compounds that contain sulfur, were in the hull samples. 

“In our study, levels of these compounds were below levels dangerous to us or the surrounding wildlife,” Van Landuyt said. “Higher concentrations of these compounds could be toxic or cause developmental issues in marine wildlife.”

Indeed, researchers estimate that sunken vessels in the North Sea may contain many millions of tons of munition, such as shells and bombs, in addition to dangerous petroleum products. The new study about John Mahn confirms that these wrecks may pose risks for ocean ecosystems, and influence the microbiology of their seabed graves, suggesting that more research into these wrecks is needed. 

To that end, Van Landuyt noted that the North Sea Wrecks project is “developing a decision-making tool to assess the potential environmental risk a wreck could pose to the environment, allowing policy makers to remediate the wrecks that are or could become harmful and preserve the safe ones (like the one we studied) for their historical value.”